I. Field of the Invention
The present invention relates generally to a system and methods for performing neurophysiologic assessments during surgery, such as assessing the health of the spinal cord via at least one of MEP and SSEP monitoring, and assessing at least one of bone integrity, nerve proximity, neuromuscular pathway, and nerve pathology (free-run and evoked) during spine surgery.
II. Discussion of the Prior Art
Surgical procedures conducted on or around the spine can be beneficial in reversing or mitigating a variety of ailments commonly suffered by patients. Despite ongoing advances in surgical methods, however, neurological impairment remains a serious concern during surgical spine procedures. The safety of the spinal cord is of paramount importance because damage to the spinal cord may have devastating results for the patient. Consequences of spinal cord damage may range from a slight loss of sensation to complete paralysis of the extremities, depending on the location and extent of damage. Assessing the spinal cord before, during and/or after surgery can provide the surgeon with valuable information on the health of the cord. Such information may allow the surgeon to initiate corrective measures if the health of the cord is compromised, thereby decreasing the chance of permanent spinal cord damage and the resulting consequences.
The spinal cord is composed of a number of nerve pathways including motor and sensory pathways. Motor pathways transmit signals from the brain to the various muscle groups of the body. Conversely, sensory pathways transmit signals from the skin and other parts of the body up to the brain. Currently, methods exist for assessing the health of the spinal cord by monitoring electrical transmission along these pathways. Degradation of an electrical signal introduced near the origin of a pathway and monitored near the end of the pathway is indicative of damage to the spinal cord.
Motor pathway monitoring may be accomplished by stimulating the motor cortex in the brain and recording the resulting EMG response of various muscles in the upper and lower extremities. This method is referred to as trans-cranial electrical motor evoked potential (tce MEP, or simply “MEP”) monitoring.
Sensory pathway monitoring may be accomplished by stimulating a peripheral nerve that enters the spinal cord below the level of surgery and recording the resulting action potentials from electrodes on the scalp or high level cervical vertebra. This method is referred to as somatosensory evoked potential (SSEP) monitoring.
While MEP and SSEP monitoring are generally effective for assessing the health of the spinal cord, data from the current methods is typically received as electrical waveforms that must first be analyzed and interpreted in order to provide meaningful data to the surgeon. Interpreting the data can be a complex and difficult task and typically requires specially trained personnel to complete it. This is disadvantageous in that it increases surgery time (additional time needed to interpret data and communicate significance to the surgeon), translates into extra expense (having extra highly trained persons in attendance), and oftentimes presents scheduling challenges because most hospitals do not retain such specially trained personnel.
Based on the foregoing, a need exists for a better system and methods for monitoring the health of the spinal cord before, during, and or after surgery, and in particular, a need for a system that has the ability to conduct MEP and SSEP monitoring while quickly presenting data to the user in a simplified yet meaningful way. A need also exists for a system for monitoring the health of the spinal cord while providing the ability to assess at least one of bone integrity, nerve proximity, neuromuscular pathway, and nerve pathology (free-run and evoked) during spine surgery.
The present invention is directed at addressing the above identified needs and overcoming, or at least improving upon, the disadvantages of the prior art.